Type of writing instrument... Ballpoint pen Pen features/materials... Water-based ink, Knock type This is a set of 10 PILOT Juice and SARASA pens. I bought these several years ago and used them, but I didn't use them all up, so I'm selling them (><) The ink levels vary from low to high. All of them can still write, but the orange and light green ones are a bit faint. I used these when I was a student, so there's a possibility that the ink might become difficult to write with. I apologize in advance if that happens. Please refrain from purchasing if you are sensitive to the condition, as they have been stored by a non-professional. Feel free to comment. #PILOT #ZEEBRA #Ballpoint pen #4 colors #Knock-type ballpoint pen #Water-based ink